<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            list-style: none;
            margin: 0;
            padding: 0;
        }

        .box {
            width: 800px;
            height: 800px;
            border: 1px solid #000;
            position: relative;
        }

        .box li {
            height: 100px;
            width: 100px;
            line-height: 100px;
            border: 1px solid #000;
            margin-left: 2px;
            display: inline-block;
            position: absolute;
            bottom: 0;
            transition: all 300ms;
        }

        li:nth-child(2) {
            left: 100px;
            background-color: orange;
        }

        li:nth-child(3) {
            left: 200px;
            background-color: yellow;
        }

        li:nth-child(4) {
            left: 300px;
            background-color: green;
        }

        li:nth-child(5) {
            left: 400px;
            background-color: aquamarine;
        }

        li:nth-child(6) {
            left: 500px;
            background-color: blue;
        }

        li:nth-child(7) {
            left: 600px;
            background-color: purple;
        }

        li:nth-child(1) {
            background-color: red;
        }

        li:hover {
            height: 800px;
        }
    </style>
</head>

<body>
    <div class="box">
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
        <li></li>
    </div>
</body>

</html>